Numerical simulation of gas-particle dense flow with LES/VFDF/SC model

Abstract

A velocity filtered density function (VFDF) transport equation is derived to solve the interaction between the gas and solid particles, in which the sub-grid scale turbulence encountered by the particles is included. The stochastic collision (SC) model is developed to deal with collision between particles based on the kinetic theory, in which the instantaneous collision rate at every time interval is obtained. Together with the large eddy simulation (LES) which is used to model the fluid flow, the LES/VFDF/SC model is developed for dense gas-particle flows. It is for the first time to consider both the SGS effect and the influence of particle collision on the particle motion in LES of dense gas-particle. Numerical simulations of 2D and 3D fluidized beds are carried out with the developed model, in which the CFD software FLUENT is applied to simulate the flow field with the LES, and the VFDF/SC model is implemented in the self-developed code with the tool of user-defined functions (UDFs) in FLUENT. Comparisons between the numerical results and the experimental data show that the dense gas-particle flow in present cases can be well predicted with the developed model.